From afc8e5bee07dbd488b34df9d7d853df89c1a4e15 Mon Sep 17 00:00:00 2001
From: Schuyler Cebulskie <Gawdl3y@gawdl3y.com>
Date: Mon, 19 Sep 2016 16:52:46 -0400
Subject: [PATCH] Add message sweeping

---
 src/client/Client.js  | 20 ++++++++++++++++++++
 src/util/Constants.js |  6 ++++++
 2 files changed, 26 insertions(+)

diff --git a/src/client/Client.js b/src/client/Client.js
index bea30e389..2349b9300 100644
--- a/src/client/Client.js
+++ b/src/client/Client.js
@@ -126,6 +126,10 @@ class Client extends EventEmitter {
 
     this._timeouts = new Set();
     this._intervals = new Set();
+
+    if (this.options.message_sweep_interval > 0) {
+      this.setInterval(this.sweepMessages.bind(this), this.options.message_sweep_interval * 1000);
+    }
   }
 
   /**
@@ -243,6 +247,22 @@ class Client extends EventEmitter {
     return this.rest.methods.getInvite(code);
   }
 
+  /**
+   * Sweeps all channels' messages and removes the ones older than the max message lifetime.
+   * If the message has been edited, the time of the edit is used rather than the time of the original message.
+   */
+  sweepMessages() {
+    if (this.options.max_message_lifetime <= 0) return;
+    const now = Date.now();
+    const lifetime = this.options.max_message_lifetime * 1000;
+    for (const channel of this.channels.values()) {
+      if (!channel.messages) continue;
+      for (const message of channel.messages.values()) {
+        if (now - (message._editedTimestamp || message._timestamp) > lifetime) channel.messages.delete(message.id);
+      }
+    }
+  }
+
   setTimeout(fn, ...params) {
     const timeout = setTimeout(() => {
       fn();
diff --git a/src/util/Constants.js b/src/util/Constants.js
index 9d15cd528..d330dce71 100644
--- a/src/util/Constants.js
+++ b/src/util/Constants.js
@@ -6,6 +6,10 @@
  * @property {number} [shard_id=0] The ID of this shard
  * @property {number} [shard_count=0] The number of shards
  * @property {number} [max_message_cache=200] Number of messages to cache per channel
+ * @property {number} [max_message_lifetime=0] How long until a message should be uncached by the message sweeping
+ * (in seconds, 0 for forever)
+ * @property {number} [message_sweep_interval=0] How frequently to remove messages from the cache that are older than
+ * the max message lifetime (in seconds, 0 for never)
  * @property {boolean} [fetch_all_members=false] Whether to cache all guild members and users upon startup
  * @property {boolean} [disable_everyone=false] Default value for MessageOptions.disable_everyone
  * @property {number} [rest_ws_bridge_timeout=5000] Maximum time permitted between REST responses and their
@@ -17,6 +21,8 @@ exports.DefaultOptions = {
   shard_id: 0,
   shard_count: 0,
   max_message_cache: 200,
+  max_message_lifetime: 0,
+  message_sweep_interval: 0,
   fetch_all_members: false,
   disable_everyone: false,
   rest_ws_bridge_timeout: 5000,